Nonaqueous electrolyte secondary batteries such as lithium secondary batteries have been widely used in electronic devices such as cellular phones, notebook computers, and PDAs.
In general, a carbon material such as graphite is used for a negative electrode active material of nonaqueous electrolyte secondary batteries. However, when a carbon material is used for a negative electrode active material, an organic solvent or the like contained in a nonaqueous electrolyte is decomposed by reduction at a surface of an electrode in the charge−discharge process of a nonaqueous electrolyte secondary battery, resulting in the generation of gas and the deposition of decomposed products. This poses problems such as the decrease in charge−discharge efficiency and the degradation of charge−discharge cycle characteristics.
For example, PTL 1 discloses, as a method that overcomes the above problems, a method in which vinylene carbonate is added to a nonaqueous electrolyte.